Rate May Be Ten Times Faster, According to New Data
From Lamont-Doherty Earth Observatory: Some 56 million years ago, a massive pulse of carbon dioxide into the atmosphere sent global temperatures soaring. In the oceans, carbonate sediments dissolved, some organisms went extinct and others evolved.
Scientists have long suspected that ocean acidification caused the crisis—similar to today, as manmade CO2 combines with seawater to change its chemistry. Now, for the first time, scientists have quantified the extent of surface acidification from those ancient days, and the news is not good: the oceans are on track to acidify at least as much as they did then, only at a much faster rate.
In a study published in the latest issue of Paleoceanography, the scientists estimate that ocean acidity increased by about 100 percent in a few thousand years or more, and stayed that way for the next 70,000 years. In this radically changed environment, some creatures died out while others adapted and evolved. The study is the first to use the chemical composition of fossils to reconstruct surface ocean acidity at the Paleocene-Eocene Thermal Maximum (PETM), a period of intense warming on land and throughout the oceans due to high CO2.
“This could be the closest geological analog to modern ocean acidification,” said study coauthor Bärbel Hönisch, a paleoceanographer at Columbia University’s Lamont-Doherty Earth Observatory. “As massive as it was, it still happened about 10 times more slowly than what we are doing today.”
The oceans have absorbed about a third of the carbon humans have pumped into the air since industrialization, helping to keep earth’s thermostat lower than it would be otherwise. But that uptake of carbon has come at a price. Chemical reactions caused by that excess CO2 have made seawater grow more acidic, depleting it of the carbonate ions that corals, mollusks and calcifying plankton need to build their shells and skeletons.
In the last 150 years or so, the pH of the oceans has dropped substantially, from 8.2 to 8.1–equivalent to a 25 percent increase in acidity. By the end of the century, ocean pH is projected to fall another 0.3 pH units, to 7.8. While the researchers found a comparable pH drop during the PETM–0.3 units–the shift happened over a few thousand years.
“We are dumping carbon in the atmosphere and ocean at a much higher rate today—within centuries,” said study coauthor Richard Zeebe, a paleoceanographer at the University of Hawaii. “If we continue on the emissions path we are on right now, acidification of the surface ocean will be way more dramatic than during the PETM.”
The study confirms that the acidified conditions lasted for 70,000 years or more, consistent with previous model-based estimates. “It didn’t bounce back right away,” said Timothy Bralower, a researcher at Penn State who was not involved in the study. “It took tens of thousands of years to recover.”
From seafloor sediments drilled off Japan, the researchers analyzed the shells of plankton that lived at the surface of the ocean during the PETM. Two different methods for measuring ocean chemistry at the time—the ratio of boron isotopes in their shells, and the amount of boron –arrived at similar estimates of acidification. “It’s really showing us clear evidence of a change in pH for the first time,” said Bralower.
What caused the burst of carbon at the PETM is still unclear. One popular explanation is that an overall warming trend may have sent a pulse of methane from the seafloor into the air, setting off events that released more earth-warming gases into the air and oceans. Up to half of the tiny animals that live in mud on the seafloor—benthic foraminifera—died out during the PETM, possibly along with life further up the food chain.
Other species thrived in this changed environment and new ones evolved. In the oceans, dinoflagellates extended their range from the tropics to the Arctic, while on land, hoofed animals and primates appeared for the first time. Eventually, the oceans and atmosphere recovered as elements from eroded rocks washed into the sea and neutralized the acid.
Today, signs are already emerging that some marine life may be in trouble. In a recent study led by Nina Bednaršedk at the U.S. National Oceanic and Atmospheric Administration, more than half of the tiny planktic snails, or pteropods, that she and her team studied off the coast of Washington, Oregon and California showed badly dissolved shells. Ocean acidification has been linked to the widespread death of baby oysters off Washington and Oregon since 2005, and may also pose a threat to coral reefs, which are under additional pressure from pollution and warming ocean temperatures.
“Seawater carbonate chemistry is complex but the mechanism underlying ocean acidification is very simple,” said study lead author Donald Penman, a graduate student at University of California at Santa Cruz. “We can make accurate predictions about how carbonate chemistry will respond to increasing carbon dioxide levels. The real unknown is how individual organisms will respond and how that cascades through ecosystems.”
Other authors of the study, which was funded by the U.S. National Science Foundation: Ellen Thomas, Yale University; and James Zachos, UC Santa Cruz.
I think the post by MichaelHart implies that carbon dioxide in the sea fertilizes the growth of the shells of shelled organisms like it fertilizes the growth of plants. It seems that the oceans might be capable of sequestering an awful lot of excess CO2. Also, it seems the variability of the Carbonate Compensation Depth provides some reserve in the operation of the carbon cycle of the oceans. This reserve might be thought of as a buffering of the system.
Have any of these studies ever arrived at a result that would show that humans had a positive affect on the planet? Surely there must be one somewhere.
But but but…won’t all the melting ice caps dilute the oceans with fresh water?
This climate catastrophism makes head hurt!
pH of fresh water is 7. pH of ocean water is about 8. Maybe we should start referring to ocean acidification as ocean “freshening?”
kadaka (KD Knoebel) says: June 4, 2014 at 4:43 am
“BTW, if anyone knows what Nick is chattering about and how that relates to measuring by simply sticking a probe into seawater, feel free to elucidate.”
DIC here, with link to TA.
Here is how to calculate.
John West says: June 4, 2014 at 4:56 am
“I’d like to know how a supersaturated solution such as surface seawater can dissolve shells.”
Sea water is on average supersaturated wrt aragonite. But it varies seasonally and with upwelling. Shell CaCO3 once dissolved won’t reform.
” the pH of the oceans has dropped substantially, from 8.2 to 8.1–equivalent to a 25 percent increase in acidity”
Really???
Really. pH is a log unit. On a log scale, 0.3 corresponds to doubling, 0.2 to increasing by 50%, and 0.1 to increasing by 0.25%. Find a calculator and punch in log(1.25) (base 10, not base e ln()). 0.09691 \approx 0.1. Technically, this means that the hydrogen ion content (hydronium) has increased by 0.25%, but of course the ocean is still predominantly basic.
Personally I have to say that this sounds like good science. Doubling the atmospheric concentration of CO_2 in 150 years may or may not cause catastrophic warming (personally I doubt that it will). It might well cause “catastrophic” changes in ocean chemistry. I’ve been, and will remain for a while at least, neutral on the issue because it is difficult to find precise proxies and because of the overwhelming confirmation bias prevalent in the community, which makes it far too easy to make up a story and look for evidence the confirm it rather than look at the evidence and make up a story to explain it (the latter process works better, go figure) but the description of the science above is at least moderately compelling.
True, most ocean life will probably adapt, although evolution on the timescale of a century is pretty tough. Some species, especially species that are already stressed by e.g. pollution or other changes and that are not “prolific” (meaning, not as many rolls of the genetic dice in reproduction), may not make it. In my opinion, though, this is a genuine area of concern. Anybody who has tried to run an aquarium knows that fish species are not all equally, or particularly, “robust” to small changes in water chemistry. This is, indeed, worth keeping an eye on.
The issue of whether it is worth spending trillions of short-run dollars and millions of human lives on is another debate entirely. Clearly it is better not to cause even mini-extinctions because alterations in the ecology can have unintended, and serious, side effects (like the die off of some important food species or even alterations in the entire oceanic food chain). On the other hand, spending trillions of dollars and millions of lives is a “consequence” of action to prevent this as well — no path may have zero consequences, and we are still stuck doing cost-benefit with incomplete information, a.k.a. “gambling”, either way.
rgb
Sorry, can’t read this crap. The ocean is not is not becoming more acidic, it is not even acidic at all .
By the way, in case it isn’t obvious, today is “I agree with Nick Stokes” day, right down the line. If this means that most of you consider me a warmist for a day, so be it. The science is the science, and this measurement (which may or may not be accurate — that is a different issue entirely and resolvable only with more/different measurements — but taken in good faith) of past ocean chemistry and correlation with radiometrically dated extinction events is not in any way equivalent to the statistically unsupportable predictions of failing GCMs used as the primary basis of the entire catastrophic climate change discussion.
rgb
As Nick Stokes already said, one doesn’t need to measure pH – even if it is done – to know the pH. If you measure two variables of seawater like DIC (dissolved inorganic carbon) and TA (total alkalinity), one can calculate the other variables. Nick has even a seawater pH calculator on the web:
http://www.moyhu.blogspot.com.au/2013/09/active-ocean-acidification-calculator.html
There were a lot of ocean measurements during the geophysical years and a few stations like Bermuda and Hawaii which have continuous series of measurements. See:
http://www.biogeosciences.net/9/2509/2012/bg-9-2509-2012.pdf Fig. 5
and
http://www.pnas.org/content/106/30/12235.full.pdf Fig. 1
The cause of the rapid PETM transition still is controversional: a hughe outburst of methane is one of the many theories, but what caused the outburst? A big meteor in the Arctic Ocean is a possibility, as that wouldn’t leave much deposit of iridium, but would trigger such an outburst of methane.
Anyway, if the mass extinction was caused by more CO2 or a lower pH, remains questionable, as a lot of other variables changed too.
Nick Stokes:
In your post at June 4, 2014 at 4:52 am you assert
That is so wrong it is risible!
The ice cores show such “events” have been the norm throughout the holocene with the delay of CO2 after temperature being typically ~800 years.
What “methane pulse” (a “popular suggestion” is not a demonstrated reality)?
And I would welcome any evidence that “our mining fossil fuel” is an “event forcing C12 higher” because although it is possible it is extremely improbable.
Richard
Interesting
“From Lamont-Doherty Earth Observatory: Some 56 million years ago, a massive pulse of carbon dioxide into the atmosphere sent global temperatures soaring. In the oceans, carbonate sediments dissolved, some organisms went extinct and others evolved”
Huh an emotive massive pulse, is this the new framing terminology? It rang a bit of bell after I noted a certain Mr R. Gates explaining his new frame.
http://judithcurry.com/2014/06/01/global-warming-versus-climate-change/#comment-580167
“HCV is a quick acronym for Human Carbon Volcano, representing the massive transfer of carbon from lithosphere to atmosphere that human activity (mainly fossil fuel burning) has created, not unlike what a natural volcano does, only the HCV had been erupting much longer (centuries) and the eruption has grown more intense with each passing decade”.
Ah massive evil Carbon pulses, ocean acidification – Human Carbon Volcano,- scary Hydrogen Bomb values, and of course back to Global Warming as it is scarier, heavens – New age verbal upchuck!
From Nick Stokes on June 4, 2014 at 5:10 am:
Yeah, right.
From an informative page with an US EPA logo:
http://omp.gso.uri.edu/ompweb/doee/science/physical/chph2.htm
I reiterate, if anyone knows what Nick is chattering about and how that relates to MEASURING by simply sticking a probe into seawater, feel free to elucidate.
Nick:
Dissolved inorganic carbon. How is the world wide level of this known to the accuracy necessary to provide an estimate of pH accurate to 0.1 today? How do we estimate the level 100 years ago?
Total alkalinity. Same two questions.
Finally. How was the temperature measured at the sample point? pH estimates from DIC and TA require temperature.
You imply this is an easy thing. I can assure you that, as someone responsible for providing regulators with these numbers, obtaining them to the accuracy you imply is labour intensive and subject to a lot of experimental error. Your assertion that this is a method of estimating pH 100 years ago, accurate to 0.1, is poorly grounded. If you are not asserting it applies to the state of the ocean 100 years ago, what basis do you have for the assertion that ocean pH has changed?
kadaka: The estimation of pH using DIC and TA at a particular temperature, is a simple exercise in equilibrium chemistry. The estimation of DIC and TA is a complicated exercise in sampling with potential for substantial errors. It should not be used to report pH unless the temperature of the sample at time of sampling and time of measurement is reported as well.
Aragonite is supersaturated in the ocean. This is just one more example where the assumption of equilibrium is hopelessly naïve.
You can’t be serious about referring to Henry’s Law, which specifically refers to constant temperature. The changes in partial pressure of CO2 these days are laughable when you try to calculate the solubility of CO2 in water by using Henry’s law. An extra CO2 molecule dissolved in a litre of water is insignificant to the pH. The greatest effect is in the temperature.
Don’t take my word for it. Refer to data that shows that CO2 in the atmosphere increases after temperature rise
richardscourtney says: June 4, 2014 at 5:25 am
“The ice cores show such “events” have been the norm throughout the holocene with the delay of CO2 after temperature being typically ~800 years.”
No. Temperatures rose, but few attribute that, generally, to CO2. The later CO2 rise was forced by temp. And yes, that CO2 rise probably was then responsible for a little more warming.
But CO2 rise is not the usual cause of warming. Immediately you have to ask – what caused the CO2 to rise? Re the PETM, that question is being asked here. In modern times, it is burning fossil fuel.
John Eggert says: June 4, 2014 at 5:46 am
“Finally. How was the temperature measured at the sample point? pH estimates from DIC and TA require temperature.”
I don’t know how extensive were the readings 100 years ago. All I am saying is that the means for measuring accurately were available. You don’t even have to do it on the spot; just take the sample to the home lab.
DIC and TA actually don’t vary that much. Here is a map of alkalinity. It varies fairly smoothly and over a not very wide range. DIC is similar – there is a map with the Wiki link I gave above. They probably measured SST at the same time, but in any case we also have good alternative measures. SST climatology, at least, is well known.
rgbatduke says:
”Technically, this means that the hydrogen ion content (hydronium) has increased by 0.25%
I think you meant 25%, but how is “per 100” a reasonable way to communicate changes in pH / acidity?
pH = H+ mol/L
0 = 1
1 = 0.1
2 = 0.01
3 = 0.001
4 = 0.0001
5 = 0.00001
6 = 0.000001
7 = 0.0000001
8 = 0.00000001
9 = 0.000000001
10 = 0.0000000001
11 = 0.00000000001
12 = 0.000000000001
13 = 0.0000000000001
14 = 0.00000000000001
8.2 = 0.00000000630957
8.1 = 0.00000000794328
The “science” is not compelling to me for they’ve shown their motive is activism/advocacy through this entirely inappropriate manner of communicating changes in acidity.
International Union of Pure and Applied Chemistry (IUPAC), published in Pure & Applied Chemistry in 1988, “Recommendations for the Determination of pH in Sea Water and Estuarine Waters”:
http://media.iupac.org/publications/pac/1988/pdf/6006×0865.pdf
Back in 1988, most common method of measuring pH in seawater was by simply sticking in a probe. The main issue was distortion from the salinity, and if you worried about it then you could calibrate from synthetic seawater solutions (buffers). Then measure by simply sticking in a probe.
Nick: The entire point of the paper is that pH has changed. If you don’t know how extensive the readings were 100 years ago, you too agree that there is no basis for saying the pH has changed. You too are saying the conclusion of the paper is based on a poorly grounded premise. This paper says more about the inadequacy of peer review than it does about ocean chemistry. And wikipedia for a source? Really?
What makes all these century and more projections absurdly ridiculous are the implied assumptions that : 1) carbon emissions levels will not only increase, but continue at the same rate for the next 100 years, or more; 2) the less carbon, the better ( a VERY dangeous notion) ;
3) something drastic needs to be done, yesterday. Actually,the biggest danger, by far, is that decarbonization will be TOO successful and carbon levels retreat to pre industrial levels.
All one needs are a pair of eyes to see that current technological and energy trends all
irrevocably lead to fewer carbon emissions, irrespective of any concerns of negative effects those emissions may visit upon us. And our totally inept President could have so easily made all this
an academic issue, had he transformed but one of his trillion dollar giveaways as a loan to construct 200 nuclear plants, which would have produced roughly 75% emission free power,and the loan paid back to the U.S. Treasury over a 30 year period,or less. But no, instead he funded projects designed to buy votes. Now there is one stupid, useless ass.
I don’t think the continents were in their present position 56 million years ago so the ocean currents were not the same. Blaming anything on CO2 at 56 million years ago is very dubious.
rgbatduke says:
June 4, 2014 at 5:14 am
” the pH of the oceans has dropped substantially, from 8.2 to 8.1–equivalent to a 25 percent increase in acidity”
Really???
Really. pH is a log unit. On a log scale, 0.3 corresponds to doubling, 0.2 to increasing by 50%, and 0.1 to increasing by 0.25%. Find a calculator and punch in log(1.25) (base 10, not base e ln()). 0.09691 \approx 0.1. Technically, this means that the hydrogen ion content (hydronium) has increased by 0.25%, but of course the ocean is still predominantly basic.
________________________________________________________________________
Check your decimal places
pH = -log(10)[H3O+] if you don’t want to go through all that activity stuff
Any 0.1 pH unit decrease is an increase in acidity as [H3O+] by 25.89%
So, pH 13.9 is theoretically 25.89% more acidic than pH 14.
The “increased acidity” by some percentage seems like propaganda to me. Acidic oceans with pH’s above 7? If someone had tried claiming acidic at pH>7 down the road on Hillsborough Street, it wouldn’t have been all that successful. But that was back when the the periodic table was much smaller.
Some critters don’t do as well at lower (basic) pH’s, but that begs the question of how they have managed to survive.
Something changed in the climate that caused a huge CO2 spike. But it was the CO2 that did all the damage.
Riiiiiiight.
Nick Stokes:
I write to request explanation of your assertions to me which make no sense.
At June 4, 2014 at 6:08 am you write
“Temperatures rose, but few attribute that, generally, to CO2.”
Really? Why then did the many not object when e.g. Al Gore did make that attribution in his sci-fi movie?
And if CO2 did not cause the temperature rises in the PETM and at the other times then what was the cause of those temperature rises?
Importantly, if CO2 did not cause those temperature rises in the past then how and why is “burning fossil fuel” doing it “in modern times”?
Thanking you in anticipation of your explanations
Richard